Currently, there are two approaches to cleaving mono-crystalline materials and the like. The first approach a low-cost, low-sophistication option, which requires a highly skill-dependent procedure (based on experience and expertise and training), teaches manually aligning by human sight a substrate and using hand tools, such as scriber pens or rudimentary cleaving apparatus (described in more detail, below). And, a second approach, which is more high-cost hut less error-prone, teaches a mechanized approach that is capital intensive in both equipment cost and operator training and, as a result, are only acquired by the top 25 semiconductor manufacturers (worldwide). This later type of cleaving apparatus is not only complicated to make and use, but requires a much larger footprint and takes valuable space in the lab and has an ongoing high cost of operation.
Examples of these two approaches include, for example, at the low-tech, low-cost, highly human-variable end of the spectrum, an apparatus described by Richard in U.S. Pat. No. 4,995,539 issued on 1991 Feb. 26. Therein a method and apparatus for cleaving a semiconductor wafer or substrate includes scribing one of the substrate surfaces with at least one scribing line to define a plane where the substrate is to be broken; placing the substrate, with its scribed surface facing upwards, between an upper and a lower foil, both foils being elastomeric and extending beyond the margins of the substrate, an adhesive serving to join the substrate to the lower foil; stretching the two foils with the substrate sandwiched in-between; applying an upward force to the lower side of the sandwich structure so as to bend the substrate, the plane of the radius being normal to the scribed lines on the convex side of the substrate and to break the substrate into individual bars as determined by the scribed lines, thus enabling the part of the lower foil to which the substrate was initially joined and to which the bars still adhere to further stretch whereby the individual bars become separated sufficiently so as to avoid mutual damage of the neighboring broken off surfaces; and removing the upper foil so that the individual bars can be further processed. Further, Richard teaches an apparatus for breaking a plate-like substrate that includes a base element having an essentially plane upper surface, its longitudinal extension being larger than that in the transverse direction; a first gripper fixedly positioned in respect of the base element, provided and arranged for releasably holding one sandwich end; a second gripper movably arranged at the base element for movement in the longitudinal direction, provided and arranged for releasably holding the other sandwich end; apparatus for adjustably displacing the second gripper in the longitudinal direction from the first gripper; and a cylindrical rod adapted to be placed on the upper surface of the base element with its cylinder axis parallel to the transverse direction and to be movable in the longitudinal direction.
Another low-tech approach includes manually scribing a line on the back side of a substrate using a scribing knife, placing the wafer over a cleaving bar from the glass industry, and manually pushing down on the work piece using two pins.
Boguslavsky et al. in U.S. Pat. No. 6,223,961 issued on 2001 May 1 teach another apparatus for cleaving crystals consisting of a pair of aligning pins facing a first cleave plane formed on a first side of a substrate, an impact pin facing a second cleave plane formed on a second side of the substrate, the substrate having a pre-scored cleave line extending between and generally perpendicular to the opposing cleave planes, and an actuator connected to at least one of the aligning pins and the impact pin.
Cornu, in European Patent No. 03347 51 issued on 1989 Sep. 27 titled for resting a silicon wafer, a cleaving bar (similar to what is used in glass cutting) arranged under, the wafer, and a pair of push bars that are interconnected and hingeably mounted to selectively apply downward presser on the wafer. The break of the wafer occurs on a line that is aligned by use of a magnification optic on the device and corresponds to a pre-formed score in the wafer. An actuator pushes upward on a rear portion of the coupled push bars to cause the push bars to travel downward towards the wafer.
Examples of known systems and methods that require considerably more capital investment, higher training levels for the operators, and more complexity include the method and apparatus for cleaving semiconductor wafers described by Smith et al. in U.S. Pat. No. 5,740,953 issued on 1998 Apr. 21. Therein, Smith teaches a method wherein, on a first lateral face of the semiconductor wafer, laterally of the workface on one side of the target feature, an indentation in alignment with the target feature; and inducing by impact in a second lateral face of the semiconductor wafer, laterally of the workface on the opposite side of the target feature, a shock wave substantially in alignment with the target feature and the indentation on the first lateral face causes a split in the semiconductor wafer along a cleavage plane essentially coinciding with the target feature and the indentation. Smith further teaches an apparatus for implementing his method. Such an apparatus includes a microscope with two eyepieces and several objectives, a vacuum chuck assembly holding means, a gear assembly including an electric step motor, tracks, and gripper assemblies, for example.
The aforementioned known methods and apparati have shortcomings, alone or in combination, including the reliance on a pre-scribed cleave line in the silicon and significant human skill and or training to operate, are highly variable due to the human factor, or are very large and require high capital initial expenditure, involve high operating costs, complexity, and are overly precise for some operations. Thus, there remains a need for a cleaving device and method that is economical to produce, inexpensive to operate and maintain, require minimal training to operate, reduce the required skill or training to operate, yet provide a highly accurate, repeatable, and clean break of a silicon wafer and the like at a precisely prescribed location, along a particular desired line.